Method of constructing a girder



June 6, 1933. B. N. WALLIS 1,913,097

METHOD 0F CONSTRUCTING A GIRDER June 6, 1933. B. N. wALLls METHOD OF CONSTRUCTING A GIRDER s sheets-sheet 2 Filed. March 14, 1932 MN RN QN MW June 6, 1933.

B. N. WALLIS METHOD 0F CONSTRUCTING A GIRDER Filed March 14", 1952 3 Sheets-Sheet -3 {gv/f fg 5 iw Maa- Patented June 6, 1933` UNITED STATES PATENT OFFICE BARNES NEVILLE WALLIS, F WEYBRIDGE, ENGLAND, ASSIGNOR TO VIGKERS l (AVIATN) LIMITED, AOI? WEYBRIDGE, ENGLAND l METHOD. on cons'rnnorrne A. Granen y Application med Maren 14, 1932, serial' no.A seasznand in Great Britain April 11, 1931. Y

This invention relates to spars, ribs and" girders (hereinafter referred to simply as girders) particularly for use inaircraft construction, ofthe type comprising tubular booms stayed apart by diagonalmembers extending in a continuous zig-zag formation from end toend of the girder, and secured to the booms by means of gusset plates, and has for its object to provide an improved 10 method for the construction vof such girders. The improved method ofconstructionacn cording to the invention will be understood from the `following description with reference to the accompanying `drawings `in Fig. 1 is a side elevation of the intermediate staying structure employed in the construction of a two-boom girder.

, Fig. 2 is a section, on a larger scale, taken along the line II-II in Fig;` 1 looking in the direction of the arrows.

Fig. 3 is a sectional plan viewillustrating the joint between successive sections of `a two-boom girder of the `kind indicated in Fig. l.

Figure 4 is `a crosssection on the line IV-IV in Figure 1, drawn to an enlarged scale but showing the tubular boom and showing the `method of securing this boom SOtothe intermediate staying structure.

`Figure 5 is a section on the line V--V in Figure 1, also drawn to an enlarged 'scale and showing the construction of the diagonal Y, .members. j Figure 6 is a similar view to Figure 2, but illustrates a` modified construction of the diagonal members, Like reference numerals indicate like parts throughout the drawings. j "The first step in buildingl up the twoboom girder` illustrated in Figs.`1-5, is to construct the intermediate' staying structure illustrated in Fig. `1. Thisstaying structure comprises gusset plates 10 to whichdia'gonal bracing members 11 are attached by means of the rivets 12 contained in areas indicated by the shading a in Figure 1 and by the bracket a in Figure 4, from whichall perpen Vdicular lines interceptthe boom, so that said "areas are opposed to the boom. The diago-l 1 as at 21 for the purpose of increasing their necting member.

set plates. The rivet holes 22'in the gusset` nal bracing members 11 are built up of pairs of T-section members, having side flanges j 18 and having flanges 15 which are inturned towards one another, interconnected by cross bracings 13 of channel section, the webs of 55 the channels being secured together by rivets 14 "through washers 14', the washers having a thickness equal to that of the flanges 15 of the T-sections. The T-sections are cut away" j at each end, as indicated at 16, and riveted to throat pieces 17, which are shaped ellip`' tically to embrace the inturned faces of the` tubular booms,`which are indicated in chain dotted lines in Figures 1 and 2 by the reference `2O. As will be seen, the cut away 65 portions 16 of the `Tfsections and the throat pieces 17 are so shaped that the diagonal `members will t snugly against the booms.

Each of the gusset plates, as will be seen, is wide enough to accommodate two diago- 7o nal members, approaching the gusset plate in opposed directions and meeting at an angleequal to or approximating to` a right angle.

Certainof the gusset plates are provided with triangular extensions, indicated at 19, apertured to receive bolts forthe attach! ment of `stays or other supports. "Certain of the gusset plates are flanged outwardly B() rigidity. j r Y j The diagonal frames, when secured by the gusset plates in their proper relation to each other, resemble in appearance a `firework of the type known as a Lcracker which has been allowed to expand into Zig-zag form, but in which the points of the zigzag are separated `from each other and have no con- Such al zig-zag intermediate staying structure is supported in a suitable jig` with the gusset plates maintained in their correct relative positions, and is then ready to receive the; tubular j booms between the inner faces `ofthe gus plates serve for the reception of the rivets for securing the gusset plates to the tubular booms. In the case when the booms are two strips 20', 20" of sheet metal bent longi! tudinally and riveted in a straight line 10C through a lap joint 20', the rivet holes in the lap joint Which coincide With the holes 22 in the gusset plates may be omitted, and when the tubes have been placed in the correct position in register With the intermediate staying structure the necessary holes may bedrilled andthe rivets 30' inserted through both the gusset plates and the double thickness of the lap joint as shovvn in Figure 4f'.

The diagonal members at the end: of the section of the intermediate staying structure, indicated in Fig. l are riveted toend frames 23. The end frames are of channel form and are provided With extensions 24, extending parallel with the length of the booms, and serving as gusset plates, tor the reception of the diagonal members Which terminate at the ends of the section. The end plates are riveted to the diagonal members by the rivets 25 diiringthe operation of' constructing the intermediate stayingstructure. When the booms have been assembledin their correct position With respect to the staying structure they are riveted to theend frames through the rivet holes indicated at: 26. Those portions ot the end frame Whichv abut against the booms are apertured, as indicated in Fig. 3., The tubular booms 20 have inserted into their ends internallyflanged strengthening sleeves 27. Adjoining sections of the girder aresecured to one another. by means of externally screwed spigots 28, screw-threaded oppositely on either side ot their medial plane and engaging with corresponding screwthreads on the inside of the strengthening sleeves 27, By turning the keyiing 29' the adjoining sections of the girder may be i tightly clamped together. As will befseen from Fig. 3, the end trames 23 are gripped between the keyring and the strengthening sleeves 27 In amodiication, instead ot' construct-ing the diagonal frames of opposedl pairs of T- section members With inturned flanges interconnected by cross-bracing members, these diagonal members may consist of channel members, as shown in Figure 6, having their ii'anges 3l and 32 securedto the gusset plates Yand having their vvebs 33 extendingtransversely, said Webs being formed With holes 34 to reduce the Weight of said members.

The method according to the inventionvis also applicable to the constructionof girders having more than tWo booms, in particulary square-'section four boom girders forl use, in the construction of aircraft Wings of the single spar type. It Will be-understood that in the case offgirders having three ormore booms, the intermediate staying structure isV i'irstbuilt up by securing the diagonal members to the gusset plates, and finally, the booms are placed in position With respect to the intermediatel staying structure and riveted to the gusset plates to give the linished girder.

Throughout the specification it has been stated that rivets are employed for securing the gusset plates to the booms. lt is, however, to be understood that the invention includes the use of nuts and bolts as a permanent securing means in place of rivets.

What I claim as my invention and desire to secure by Letters Patent is LA method for the 'construction of a girder, particularly for use in aircraft construction, of the kind comprising tubular booms, diagonal bracing membersand gusset plates securing the diagonalv members to the booms, Which comprises the steps of forming tubular booms by riveting together sheet metal. strips along opposed lapl joints omitting the rivets in those portions of the lap joints Which are to receive the gusset plates, building up.- an intermediate staying structure of zig-zag formation.. by riveting the diagonal members to the gusset plates, and nally completing the sti-ucture by securing the'booins tothegusset plates by meansof rivets extendingl through the gusset plates and the double thickness of the lap-joints. Y

2. A- method for the construction of a girder, particularly for use in aircraft construction, of the kind comprising tubular booms,` diagonal bracing meinbersand gusset plates securing the diagonal members to the booms, Which` comprises the steps of forming tubular booms by juxtaposing bent sheet metal strips With their borders overlapping,v drilling holes through said overlapping; borders, but omitting the holes in those portions of the borders-Which arevto receive the gusset plates, and securing the strips together by means of rivets inserted through. said holes, building up an intermediate staying structure of zig-zag formation by riveting the diagonal members to the gusset plates, assembling the booms in register With the intermediate staying structure, drilling holes through the gusset plates andthe corresponding portions ot the overlap joints in the booms, and iinally securing the booms tothe gusset plates by rivets inserted through said holes.

3. A method for the constructionv of a girder, particularly for use in aircraft construction, of the kind comprising tubular booms, diagonal bracing members and gusset plates securing the diagonaly members to the booms, Which comprises the stepsv andI facingl one another, by means of cross.

bracingsinterconnecting said flanges, attachingthe ends of said diagonal members to throat pieces shaped elliptically to lit the booms, riveting the diagonal bracings to the gusset plates to form an intermediate staying structure of zig-zag formation, and then completing the structure by riveting the booms to the gusset plates.

`In witness whereof I have hereunto set my hand. v

BARNES NEVILLE WALLIS. 

